Very many techniques are already known for folding stroller frames. In general, an attempt is made to reconcile at least some of the following objectives:                efficiency of folding, the stroller should be as small as possible when folded so as to facilitate its storage and transport, for example in an automobile vehicle,        simplicity of folding and unfolding manipulations; the user should be able to perform these operations as simply as possible        strength and safety of the transported child,        simplicity and low cost of manufacturing.        
One category among the various known frame types is called “broken folding”. According to this technique, when in the unfolded position, the push arms are located approximately along the extension of the front stands and tilt with respect to them when folding. The push arms usually tilt downwards, the top end of the push arms moving towards the rear wheels.
Techniques are also known according to which the push arms tilt upwards, such that the top end of the push arm moves closer to the front wheels. This type of technique has been developed particularly by the holder of this patent application for so-called “off-road” strollers that are provided with large wheels (compared with conventional strollers), usually fitted with inflatable tires.
Another known technique is shown in FIG. 1. According to this technique, each push arm 1 can slide parallel to the front strut 2 between an extended position in which the push arm forms a continuation of the front strut and a folded position in which the push arm and the front strut corresponding to it are arranged side by side. Each rear strut 3 is articulated close to its top end onto the corresponding front strut.
These various techniques usually have a common factor, by which push arms slide with respect to the front struts. These various elements are made in the form of metallic tubes and sliding is based on a constant principle consisting of using a connecting part 4 installed fixed on the front strut and provided with a slide, at a spacing from the attachment point of the front strut, in which the push arm can slide parallel to the front strut while being separated from it.
With this mechanical assembly, it has been possible to propose several folding techniques using this type of sliding, particularly the techniques mentioned above.
However, this design principle introduces several disadvantages.
The push arm is only guided in a relatively short portion of the connecting part. With part wear and progressive appearance of gradually increasing clearances between them, sliding is affected by offset phenomena so that it becomes difficult for the user to perform the above folding and/or unfolding operations.
Furthermore, connecting parts and push arms are likely to get dirty, to a variable extent depending on the paths along which the child's stroller is taken, and can cause blockage of sliding during folding or unfolding.
Moreover, during folding and unfolding operations of the stroller, the user or the child being carried might accidentally slide his or her fingers into the space between the push arm and the front strut, at the risk of getting them trapped with more or less serious consequences.